1. You Already Know That… Noble gases are the least reactive
Alkali metals & halogens are the most reactive
All elements want to follow the octet rule
This states that elements want full s & p orbitals, or 8 valence electrons, except H, which only wants 2

2. You Also Know That… Ions are charged atoms
Cations are atoms with positive charges
They are usually on the left side of the periodic table.
Anions are atoms with negative charges
They are usually on the right side of the periodic table.

3. Stable Ions
Some ions have Noble Gas Configurations, or complete octets
They only give up a certain number of electrons
Ca will give up it’s 2 valence electrons becoming Ca2+ which has 8 valence electrons

4. Stable Ions (cont.) Some do not have complete outer shells
They are the transition elements & a few other metals
Most can give up different amounts of electrons
Fe can give up 2, 3 or 4 electrons becoming Fe2+, Fe3+ or Fe4+

5. Connections
Elements follow the easiest path by removing, or gaining, the least amount of electrons
It’s easier for Ca to remove 2 electrons than to gain 6 electrons
Ions have different properties than their parent elements since electrons determine properties

6. Types of Ions Monoatomic Ions form from one atom
Ca2+ N3- Fe4+ O2- K+ Cl-
Polyatomic Ions are formed from 2 or more bonded atoms
NO3- NH4+ CN- CrO42-

7. Ionic Bonding
Ions combine to create salts with a crystal lattice structure
Tightly-packed bonded atoms
They are brittle, have high melting & boiling points, and are good conductors of electricity when dissolved in water

8. Ionic Bonding
Ions with different charges bond together to form compounds
A cation will bond with an anion
Charges must cancel out when bonded
Ca2+ & N3- cancel out by there being N3- & 3 Ca2+ to make Ca3N2
Criss-Cross Method: the charge of one ion becomes the subscript of the other

9. Naming Compounds
Binary compounds, compounds with just 2 elements, combine monoatomic cations and anions
A compound is named by combining the names of its ions
Ca2+ is “calcium” & N3- is “nitride”
So Ca3N2 is called “calcium nitride”

10. Writing Formulas
When starting with a compound's name, break it apart and write the separate ions
Sodium Chloride is composed of a sodium (Na+) and a chloride, or chlorine anion (Cl- )
Then combine the two ions
Na+ + Cl- is NaCl

11. Writing Names
When starting with a polyatomic compound's formulas break it apart and write the separate ions
(NH4)3PO4 is composed of an NH4+ (ammonium) and a PO4-3 (phosphate)
Then combine the two names
Ammonium Phosphate

12. Covalent (Molecular) Compounds
When 2 non-metals combine, they use prefixes to tell their amount
If there is only one of the first element, you DO NOT use mono-
Mono = 1
Di- = 2
Tri- = 3
Tetra- = 4
Penta- = 5
Hexa- = 6
Hepta- = 7
Octa- = 8
Nona- = 9
Deca- = 10

13. Naming Acids Ion Name Acid Name
_______ ide makes Hydro____ic
Hypo____ite makes Hypo___ous
____ite makes _______ous
____ate makes ________ic
Per___ate makes Per_____ic

14. For example, dealing with Cl.
Chloride
Hydrochloric Acid
Cl-
HCl
Hypochlorite
Hypochlorous Acid
ClO-
HClO
Chlorite
Chlorous Acid
ClO2-
HClO2
Chlorate
Chloric Acid
ClO3-
HClO3
Perchlorate
Perchloric Acid
ClO4-
HClO4

15. Nomenclature Review The Criss-Cross Method switches charges
Remember to put the charge on the OUTSIDE of the parentheses for Polyatomic Ions – Magnesium Phosphate Mg3(PO4)2
Ionic Compounds combine the names of the ions
Use the Roman Numeral for elements with more than one charge – Tin (II) Chloride, SnCl2
Covalent Compounds use the prefixes to tell how many of each element – Dinitrogen Pentoxide, N2O5